Engine turns over but won't start............

[davidsl500]

So, I gave pin 87 a 12v+ feed and the pumps run continuously but still not even a whiff of a start - not a kick to be had.. I have loosened the pipe slightly on the fuel return and I get fuel seepage. As its an early R129 500SL there is no fuel distributor as such - its a rail and I can't seem to find a cold start injector..

Any more idea's anyone? It's got me totally mystified at the moment as it has always been a first time instant starter. Although I appreciate everything works until it breaks!

 

[television]

So no fuel distributor, see what I can after a bite to eat.

 

[television]

David, I am lost on this one. KE was fitted till end of 92, you must have a fuel distributor behind the throttle.

 

[davidsl500]

I shall take a pic of the layout after a quick snack... I don't even seem to have a MAS unit either! I do wonder about this car sometimes as nothing seems to be as it should!

 

[davidsl500]

Ok, so here's some pictures of the fuel feed and return, engine bay and a bulkhead shot where the MAS and I think the OVP are supposed to be.....

I can't find any fuel distributor - there fuel feed runs directly into the rail around the engine and then back to the return.

I cant test the pressure on the rail so I am going to drain the tank and replace the filter as I am still a bit suspicious whether there is enough fuel getting forward....

 

[grober]

That looks like a LH jetronic system [sequential] which wasn't introduced till 1992 which is puzzling if your car is a 1991 model. This means you will have the later modular system which will be inside that light silver coloured box in picture 1.

 

[grober]

This is the best functional description of that LH system I know of. http://www.k6jrf.com/MB_S500.html

 

[television]

That looks like a LH jetronic system [sequential] which wasn't introduced till 1992 which is puzzling if your car is a 1991 model. This means you will have the later modular system which will be inside that light silver coloured box in picture 1.

Thanks I was wondering if LH, so I will be off again seeing what I can find as well. As you say really odd that no KE

 

[mattkh]

Hi
Wet plugs.
Time to get one out and check.

 

[television]

David, time to make a blink code reader

http://www.w124performance.com/docs/mb/diagnostics/DTC_List_W124_M119.pdf

http://www.mbslk.de/files/artikel/r170_fehlercodes.pdf

 

[davidsl500]

Thanks Malcolm. I have some 12V LED’s already resistored up and plenty of momentary switches so I shall knock one up when I have a moment this week. Just need something novel to build it into…

I drained the tank and dropped the fuel filter out as the last job yesterday. The fuel that came out was decidedly yellow and milky and I am wondering whether the fuel filter is partially clogged. The pumps didn’t seem “strained” when running but maybe there just isn’t enough pressure to fire the injectors.. I expected the fuel to be pretty clean since it was fresh fuel going in the tank and running the pumps a while.

I did replace both pumps and filter in the summer of 2013 when I left the car idling and ran the tank dry – which killed both pumps. I haven’t really used the car much since then though it has always started first turn - whenever I have remembered to start it.. Fingers crossed that a new filter might just do it as I am sure it is a fuel related issue.

The car had its pre delivery inspection and was first registered 26th April 1991 so it’s definitely pre 1992. I do have to cross check everything I buy for this car as anything catalogue listed doesn’t seem to be right!

I shall order up a fuel filter and let the saga continue!

 

[television]

Could be a learning curve for LH for me. Interesting that the ECU is the same.

 

[davidsl500]

Well plumbed a new filter in last night put some fresh fuel in and its still a no go - turns over but not a hint of a kick from it. It kicks and runs briefly on ether so it looks like the electrical side is ok.

I knocked up a quick blink code reader so looks like I shall be reading codes the weekend. It only takes a few minutes to build it - but I didn't have anything to mount it into ...so I went for the unusual....:lol:

 

[davidsl500]

Blink Codes

So finally managed to try out my Blink Code Reader and here are the Results:

A reminder on the car - R129 500SL WDB129066 1199602 engine

Pin 4 - 11, 13
Pin 6 - 12, 23, 30
Pin 7 - 3, 8, 14
Pin 8 - 9, 10, 11, 12, 13
Pin 11 - None
Pin 13 - None
Pin 14 - Lit the LED when plugged in and didn't respond further
Pin 17 - 1
Pin 21 - 2, 4
Pin 22 - Lit when plugged in then gave - 3, 6, 8 and then when back to lit
Pin 23 - None
Pin 30 - None
Pin 31 - Lit when plugged in then gave - 7, 12 and went back to lit


Anyone like to take a guess whilst I try to make sense of the Diag codes myself?

 

[television]

Did you use the codes from http://www.mbslk.de/files/artikel/r170_fehlercodes.pdf

I do have the mercedes version but not possible to access today

 

[davidsl500]

Hi Malcolm, I have various charts including the one you link to. My biggest issue is trying to work out which one applies to my car! Bearing in mind mine should be KE and it seems to be LH on the injetion. The codes on pin 4 suggest secondary air injection open or short circuit and an open or short circuit temp sensor but where to find them !

more internet searching i think...

 

[television]

The air temp sensor is on the air box I believe, the water temp top front of head

 

[Ned]

Hi Davidsl500

There seems to be something not right with your car, the 129066 chassis had the 119.960 engine fitted which has CIS injection. You car looks to have LH injection which is the 119.972 engine that was fitted to chassis 129067. You also have the 38 pin diagnostic plug as opposed to the 16 pin plug in the 129066 chassis.

Do you know if the car has had an engine swap in the past as this could explain it.

Regarding the codes refer to the tables for 129067 chassis with LH and not the 129066 CIS codes. I will try and copy my codes guide for you.

 

[Ned]

Hi Davidsl500

just looked up your codes and your problem looks to be with the Base module. All the codes for pin 8 are related to interuption of voltage supply to LH control module and interuption of voltage to fuel injectors from the Base module.

I am not sure but I think it may be the module with a number of fuses on the top of it. Worth checking all the fuses.

I can't upload the file as it's too large, if you pm me your email I will send it to you.

regards
Ned

 

[davidsl500]

So the fun continues and its throwing up some other mysteries as well....

I took the alu top off the "apparatus case" to reveal the control units. The back one is the Base Module 011 545 97 32 GM which has 4 fuses on top. The fuses were fine and a look inside the unit revealed 3 double relays - all contacts sparkly clean and all the solder joints to the pcb look fine....

Having found this link http://www.mbpartsworld.com/showAssembly.aspx?ukey_product=7346244&ukey_assembly=1073644

It would appear that the LH Control unit is next door to the Base Module so I shall whip that one out and have a look inside that..

And now the mystery.... The moulding manufacture date on the Base Module inside reads 1994......on a 1991 car..... I did catch a glimpse of an external label on control unit next to this which also read 1994... Bearing in mind that my car should have KE Injection and mine has LH, that brings up all sorts of questions.....